"They're about the size of a pin head probably and they physically chew on the young crops so they can actually knock it around quite badly, particularly if the crop is under a bit of stress from the frost," he explained.

"So generally speaking you need to go out and spray them to protect the crop."

Mr White says, on top of costly spraying, farmers have to wait longer for their crops to come up, with cooler soil temperatures slowing growth.

"[For] anybody who has just sown crops, it can make quite a difference on how that comes up," he said.

"While soil temperature is good, around 15 degrees or whatever, they'll come up in a week to 10 days. Once that soil temperature has dropped dramatically it can take a fortnight to three weeks sometimes for the crop to come up.